std::forward_list<T,Allocator>::before_begin, cbefore_begin

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Containers library
Sequence
(C++11)
Associative
Unordered associative
Adaptors
Views
(C++20)
 
 
iterator before_begin() noexcept;
(since C++11)
const_iterator before_begin() const noexcept;
(since C++11)
const_iterator cbefore_begin() const noexcept;
(since C++11)

Returns an iterator to the element before the first element of the container. This element acts as a placeholder, attempting to access it results in undefined behavior. The only usage cases are in functions insert_after(), emplace_after(), erase_after(), splice_after() and the increment operator: incrementing the before-begin iterator gives exactly the same iterator as obtained from begin()/cbegin().

Parameters

(none)

Return value

Iterator to the element before the first element.

Complexity

Constant.

See also

returns an iterator to the beginning
(public member function)
(C++11)
returns an iterator to the end
(public member function)